It is known to construct a light source for an optical apparatus from a plurality of light source members and perform control so as to maintain the amount of light emission of the optical apparatus light source constant by detecting the amount of exposure from the optical apparatus light source in an apparatus that provides illumination for exposure using the light produced by the optical apparatus light source (Japanese Unexamined Patent Publication No. S61-264361). In such an apparatus, it has been extremely difficult to control the amount of light from the optical apparatus light source to a constant level.
Especially, in the case of an apparatus, such as a photographic exposure apparatus, that requires high quality exposure, with the prior art method it has been difficult to accurately maintain the entire amount of light at a constant level.
On the other hand, no studies have ever been made on how the plurality of light source members should be placed, in particular, the placement pitch of the light source members, in order to control the amount of light from the optical apparatus light source to a constant level.